


Sharks

by MaggicSorceress



Series: Maggic's Undertale Mermaid AU [5]
Category: Undertale (Video Game)
Genre: Alternate Universe - Merpeople, Dream is just happy to be there, Dust and Horror are little shits, Fluff and Humor, Gen, M/M, Nightmare does not have a fun time, Same with Blue, he does not appreciate the teasing boys, hi i love mermaids so have another one
Language: English
Status: Completed
Published: 2020-07-25
Updated: 2020-07-25
Packaged: 2021-03-05 22:28:52
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,381
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25502896
Author URL: https://archiveofourown.org/users/MaggicSorceress/pseuds/MaggicSorceress
Summary: Dream is slightly concerned about the people his brother is hanging around.Turns out, he had no reason to be.
Relationships: Dream/Cross (implied), Nightmare & Dream, Nightmare/Killer
Series: Maggic's Undertale Mermaid AU [5]
Series URL: https://archiveofourown.org/series/1850452
Comments: 12
Kudos: 93





	Sharks

Dream and Nightmare weren’t blood related, hardly anyone down here was anyway. Rather, their mother had adopted them both, as they had both been abandoned. That knowledge, that they had found out when they were older, wasn’t enough to derail their relationship. In their eyes, they were brother’s in every way that mattered. Regardless of the differences of their biological species.

Dream loved his brother, but there were times when his ‘friends’ just couldn’t figure out why.

_“He’s too quite.” They said. “Does he even know how to speak?”_

_“He’s just shy.”_

_“He always looks angry.” Another added. “Does he ever smile?_

_“Sometimes!”_

Eventually, and he hated to admit it, he stopped gracing their questions with a response. If they were so curious about his brother, they should go talk to him themselves. He never thought the questions came from anywhere other than curiosity, and he honestly hadn’t thought that his friends were being mean to his brother until he saw it in action.

Dream stopped hanging out with them shortly after, which Nightmare had been very against. He hadn’t wanted Dream to not have friends because of him, but Dream was stubborn and very firm about his decision.

_“I don’t want to hang around those kinds of people, Night.” Dream had said. “Besides! You’re way more important to me than they could ever be!”_

Dream had always been content with that, knowing that he would always have his brother no matter what.

But, as they grew older, they began drifting apart. They still talked and were on pleasant terms with each other, as they still very much cared about the other, but they grew to live vastly different lives.

Dream wasn’t very happy when he found out his brother was hanging around with sharks, but maybe that was a little species-ist of him. If he was honest, they scared him and, although he trusted Nightmare, he was worried about the other’s safety. Nightmare, however strong he was, really wouldn’t be able to put up much of a fight. Nothing like that had happened so far, so Dream counted his blessings and tried not to make a fuss about it.

Dream himself tried to live a relatively normal life. He worked at a coffee shop with his two best friends, lived in a small cavern about a fifteen minute swim from work, spent his free afternoons going on a wild exploration or something similar with Ink or Blueberry, and tried to not stress about whether or not his brother was dead in something’s stomach somewhere. Overall, however, he had no complaints about his life.

The first time he met the sharks he hoped were Nightmare’s friends was completely accidental. Blue had talked him into going looking for shipwrecks one day after work and Dream, even though he was tired, agreed to go with him for a few hours. They stumbled across one fairly quickly, only twenty or so minutes out of town, and they were eager to start exploring it, but then, as Blue entered a rather large hole in the hull, he came tailing out of it not thirty seconds later being chased by a broad shouldered mer with large bandages wrapped around one half of his face and a large grey shark tail. Blue grabbed Dream and tugged him along as he fled.

“Gottagogottagogottago!!” Blue exclaimed.

“Horror, stop it!” A voice called out, firm and commanding. The shark, or Horror as he was apparently called, halted his chase, and whipped around to stare back at the shipwreck. Out of the crack in the hall, Nightmare emerged, tentacles flaring as he swam out and changing from a dark grey to their normal red and white stripes. As he swam out, three more shark merpeople emerged and swam around the ship, coming to float up by the deck of the ship. They peered over the crumbling railing, all their hair coloured varying pale shades and eyes large as they stared down at the other three fish.

“I’d appreciate it if you didn’t rip my brother to shreds.” Nightmare finished.

Relief washed instantly over Dream and he left his friend’s side in favour of swimming quickly over to Nightmare, clutching his brother’s arm and hiding partially behind him.

“You have no idea how thankful I am to see you.” Dream breathed. Nightmare huffed an annoyed sigh as a tentacle drifted upward to wind around Dream’s wrist.

“You don’t really have to be afraid of Horror, he’s harmless.” Nightmare said. “Why are you here anyway?”

“Me and Blue just went exploring.” Dream explained. “I didn’t expect to find you here.”

“Wha’ d’you mean I’m harmless?” Horror cried indignantly, swimming over to where the two brothers floated.

“I mean you’re harmless.” Nightmare reiterated as a tentacle reached out to poke the shark on the nose, smirking to himself. Horror frowned, though it ended up looking more like a pout, and bit sharply into the water where Nightmare’s tentacle had been only moments before. If Nightmare was startled by the display of pointed teeth or the sudden aggression, he didn’t show it, rolling his eyes and overall unamused.

There came a chuckle from the deck of the shipwreck. “C’mon, Horror!” One of the other sharks called, this one with almost grey hair and mismatched eyes. “Make him ink!”

“Oh, fuck off, Dust!” Nightmare said, glaring at Dust over his shoulder.

“Yeah.” Came another voice, this time from inside the shipwreck, as yet another shark emerged from the hole in the hull. He had the same pale hair and skin as the others, but his eyes were dark, scarring running down his cheeks from under his eyes, and his tail was speckled. He swam up along the side of Nightmare that Dream wasn’t on, dragging his hand along Nightmare’s shoulder as he passed. “Besides, I’m the only one that gets to do that~.”

Nightmare flustered, despite his twin’s obliviousness, and lashed out at the shark with a fist and a few tentacles, frowning deeper when the other only laughed and swam out of reach. “Shut up, Killer!”

“What?” Killer asked innocently. “I wasn’t implying anything by that.”

Nightmare opened his mouth to retort, but paused when Dream poked him lightly on the arm and looked at him with wide curious eyes. It didn’t take Nightmare long to decipher what his brother was trying to ask him without words.

And it didn’t stop him from sighing in annoyance.

“Right…” Nightmare began as Blueberry swam up to Dream’s opposite side. “Dream, Blueberry, this is Horror, Dust, Cross, and Killer. Guys, this is my brother Dream and his friend Blueberry.”

As Nightmare sped through an introduction, Dream fought hard to remember which mer had what name. Horror was the one with the bandages, it seemed, and Dust was the one with the interesting eyes. The shark that had previously been teasing his brother was Killer, and that left…

On the far side of the shipwreck, on the main deck with his arms folded and resting on the crumbling wooden railing, drifted a fourth shark with a large tail and long faded hair that was pulled back into a low ponytail. When the shark, who had to be named Cross if Dream was listening well enough, saw Dream staring at him, he gave him a small tight-lipped smile and raised a hand in a half wave. Dream felt a smile tug at his lips as he copied the motion.

“It’s nice to finally meet you all.” Dream said, still feeling slightly uncomfortable under all of their gazes. “I’m glad my brother has friends watching out for him.”

Dust snorted. “It’s more like the other way around.”

“Tell me about it.” Nightmare said, clearly exasperated. “You four can’t stay out of trouble for ten minutes if I leave you alone.”

“Yeah.” Killer said as he swam a slow circle and came back over to where Nightmare, Dream, and Blueberry floated, sliding up to the side that Dream wasn’t on and responding to Nightmare smacking his arm by sliding one around the octopus’s waist. “We’d be lost without mama Nootmare.”

Nightmare hit him again. “Call me ‘Nootmare’ one more fucking time and I swear to god I will strangle you.”

Killer raised an eyebrow, smirking, and Dust gagged in the background.

“That’s kinky.” Horror stated.

“Can you two stop flirting for five fucking minutes?” Dust said. “Just get a room already.”

“We’re _not_ flirting!” Nightmare said, tentacles flaring and cheeks turning blue as the blood rushed to his face.

Killer, growing tired of getting smacked, extricated himself from Nightmare’s side and swam back over to the shipwreck. “ _I_ was…”

Nightmare sighed and frowned, willing his blush to go away as he scowled.

“Just ignore Killer.” He said to his brother. “He’s an idiot.”

“….What’s going on?~” Dream sang as he pieced together both the comments from the sharks and Nightmare’s embarrassment.

“Nothing!” Nightmare defended, folding his arms over his chest when Dream maneuvered to float in front of him and place his hands on his shoulders, staring at him with wide golden eyes.

“Nighty…?” Dream said, pouting although a twinkle remained in his eyes.

“There’s nothing going on!” Nightmare said.

“Do I seriously have to pry it out of you in front of all your friends?”

“N-“

“You don’t have to!” Killer called from where he lounged in the water by Cross, throwing an arm around the other shark’s shoulder as he grinned down at Dream, playfulness in every minute detail of his expression. “Nightmare and I are dating!”

Dream turned to his brother with an unimpressed look, but the flat line of his lips twitched upwards at the sight of how embarrassed a simple statement was making Nightmare. He fought down the urge to giggle at how the blue of the other’s blush had bled down to his collar bone and out along his shoulders, and how the other’s normally burgundy and white striped tentacles were twisting and curling beneath him, fluctuating between a soft pink shade and a deep blue one that almost matched his blush. Warmth bubbled in Dream’s chest at the sight he couldn’t resist pulling his brother into a hug.

“You’re so cute, Night.” Dream teased; the giggling he was trying so hard to keep to himself worming its way into his voice.

“Shut up!” Nightmare shouted as his embarrassment grew, curling in on himself and hiding his face in his hands.

“Isn’t he?” Killer agreed from Cross’s side.

Pushing himself out of Dream’s embrace, Nightmare whirled around to face his boyfriend. “Shut up, you asshole! I was going to tell Dream eventually; you didn’t have to come out and say it like that!”

“Say it like what, babe?” Killer said with a fond roll of his eyes. “I was just stating the obvious, even if it was blunt.”

“It…It wasn’t…” Nightmare stumbled, tentacles curling in close to him. “It wasn’t obvious…”

“I mean…” Cross said, smirking. “Your brother did deduce that something was up all on his own.”

“Bullshit!” Nightmare said. “Horror and Dust wouldn’t stop fucking teasing me! That’s how he deduced shit!”

Horror and Dust, from where they drifted up on the deck of the shipwreck, snickered and exchanged high fives. Killer laughed and Nightmare turned to him again.

“You didn’t help either, you jerk!”

Killer raised his hands in mock surrender. “What did I do? I’m not allowed to give my boyfriend affection when his brother is around?”

“No!”

“No, I _am_ allowed?” Killer said, raising an amused eyebrow and sending Nightmare a sharp-toothed grin. “Or no, I’m _not_ allowed?”

“You’re _not_ allowed!” Nightmare cried, embarrassment having yet to die out.

Cross chuckled and gave an exasperated shake of his head.

“You two are impossible, I swear.” He mumbled.

“Don’t be embarrassed, Nighty.” Dream said, finally deciding to insert himself back into the conversation. “I’m happy for you!” He paused for a moment, pouting. “Even though you could have told me yourself…”

“I was going to…” Nightmare muttered. “Just…not like this…”

“D’awww…” Dust cooed, teasing, from his spot next to Horror. “Wittle Nighty-Whitey was embarrwassed to tell his wittle brother about his boyfwend.” Horror snorted and, Nightmare, in a moment of shame induced rage, shot through the water like a torpedo at the two of them, growling in annoyance when they darted away, still laughing to themselves.

“Come back here and face me, you fucking cowards!” Nightmare yelled as his tentacles spread, curling and lashing as he gave chase to the two instigators.

Dream watched their chase for a moment or two before he turned to glance back at Blueberry, who had been watching this all unfurl with an amused, and slightly confused, smile on his face. When he met Dream’s stare, they both shared a giggle, before their focus was yanked back to the scene in front of them when Nightmare let out a startled shriek.

Killer had snuck up behind him, winding his arms around his waist and holding him tightly against his chest in order to stall the other’s frantic swimming. Nightmare twisted in his arms, tentacles wrapping around any part of Killer they could reach as he tried to break free. His struggled faltered, however, when Killer settled one hand on the small of his back and used the other to cup his jaw, smoothing the skin of his cheek with the pad of his thumb. Then, quickly, he leaned in and pecked the other on the lips, whispering something Dream couldn’t hear.

“Aww…” Dream and Blue breathed at the same time.

Cross, who had swum over to the two while the scene was unfolding, gave an airy chuckle and shook his head.

“They seriously are impossible.” He said before he turned back to them, extending a hand. “It’s nice to meet the both of you. Nightmare talks a lot about you, Dream.”

Dream took the offered hand, chest clenching at the small and somewhat shy smile that Cross had offered him, and shook it. “It’s nice to meet you as well Cross! I hope it’s only been good things he’s been saying.”

“Oh, don’t worry.” Cross said, shaking Blueberry’s hand. “It has been.”

Dream, feeling a little lighter than he had in a while, smiled back at Cross.

Maybe Nightmare’s friends weren’t so bad after all.

**Author's Note:**

> Hi y'all! Here's another mermaid fic even tho mermay is waaaaay over.  
> Killer: Tiger shark  
> Nightmare: Mimic octopus  
> Dream: Blueback herring  
> Blue: Blue striped grunt  
> Horror: Bull shark  
> Dust: Black tip reef shark  
> Cross: Whale shark  
> Also the idea of Nightmare changing colour when he gets super embarrassed is so fucking adorable to me that I just had to implement it so, sorry not sorry :p  
> Hope you guys liked it! Comments and kudos are always appreciated! <3  
> -Maggic


End file.
